The present invention relates to compositions for treating, for example, disinfecting, cleaning, soaking, conditioning and wetting contact lenses. More particularly, the invention relates to multi-purpose solutions useful in treating contact lenses, for example, for disinfecting contact lenses, for removing deposit material from contact lenses, for soaking, conditioning and/or wetting contact lenses and the like, which provide substantial comfort and acceptability benefits to the users of such solutions.
Contact lenses need to be periodically treated, for example, disinfected, cleaned, soaked and the like, on a regular basis because of the tendency for a variety of ocular and environmental contaminants, microbes and other materials to accumulate on the lenses and/or the need to provide the lenses in suitable condition for safe and comfortable wear. User compliance, that is users treating contact lenses on a regular and consistent basis, is important in order to promote ocular health and to avoid problems associated with contact lens wear. User compliance is enhanced when the treatment solution employed provides high degrees of lens wearer/user comfort and acceptability. Therefore, it would be advantageous to provide compositions for treating contact lenses which provide such comfort and/or are accepted by contact lens wearers/users of such compositions.
Fu U.S. Pat. No. 4,323,467 discloses an aqueous composition combining a poly(oxyethylene)-poly(oxypropylene) substituted ethylenediamine surfactant, a germicidal agent, a viscosity builder, a tonicity agent, a sequestering agent and water for treating rigid contact lenses. This patent discloses a germicide, such as thimerosal and/or benzalkonium chloride, in a concentration of 0.0005%-0.05%. The Fu patent does not disclose the use of any specific buffer. Although the compositions of the Fu patent have multiple utilities, there is a potential for eye discomfort and/or irritation, for example, because of the relatively high concentrations of germicide and the apparent lack of pH control.
British Pat. No. 1,432,345 discloses a contact lens disinfecting composition including an ophthalmically acceptable biguanide in a total amount of from 0.0005% to 0.05% by weight. This British patent discloses that the solution preferably has a pH of from 5 to 8 and employs a phosphate buffer. The patent also discloses employing additional bactericides, thickening agents and non-ionic surfactants, as well as disodium EDTA in concentrations of at least 0.1%. Although these compositions are effective as contact lens disinfectants, they do pose a risk of eye discomfort and/or irritation, for example, because of the relatively high concentrations of biguanide and EDTA employed.
Ogunbiyi et al U.S. Pat. No. 4,758,595 discloses an aqueous solution of a biguanide in an amount of 0.000001 to 0.0003% weight percent in combination with a borate buffer system, EDTA, and one or more surfactants. This U.S. Patent additionally states that conventional buffers, other than the borate buffer, can be used but only in conjunction with increased amounts of biguanide. Thus, the general conclusion of this U.S. Patent is that if reduced amounts of biguanide are to be used, a borate buffer is essential. Although such compositions are useful, the potential for ocular discomfort and irritation in a relatively large percentage of the total population still exists, for example, because of the requirement that a borate buffer be employed.
There continues to be a need to provide new contact lens treatment systems, for example, multi-purpose solutions, that effect the desired treatment or treatments of the lens and, at the same time, provide substantial, preferably enhanced, lens wearer/user comfort and acceptability.